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While waiting for my new regulator/rectifier to arrive I took a look at another area for electrical improvement, voltage to the coils. A quick voltmeter test showed that there is a reduction at each coil of 2.3 volts compared to the voltage at the battery. At startup this means that the coils were only seeing 10.2 volts of electricity instead of 12+ volts. A common modification is to install a relay that will provide full voltage to the coils by connecting the coils directly to the battery via the relay.

Here is a wiring diagram of what the finished modification will look like:

Each of the coils has an orange with with white stripe lead that provides voltage to the coils after passing through the ignition switch and kill switch. I removed these two wires from the coils, paired them together and joined them to pin 86 on the relay to be the trigger.

New wires were then run from 87 pins of the relay back to the original location on the coils where the O/W wires were connected. I used 16 gauge white wire for each of these new connections.

I then ran 12 gauge black and red wire back to the battery to provide full power to the relay through pins 30 and 86. The relay is wire tied to the small frame cross member behind the coils and will be under the fuel tank when in operation.

I may tweak this wiring as I work on a single point ground and install the new regulator/rectifier, but for now, the coils are only seeing a 0.1 volt drop from battery voltage with the relay in place.

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So far this year my focus has been on making sure that the electrical system on this 35 year old motorcycle is healthy. Last thing you want to do is get far from home, go to start the bike, and realize that your battery is dead since it wasn’t being charged the whole time that you have been riding. The guys at GS Resources have come up with a series of tests beyond what is in the service manual to determine the health of you stator, regulator/rectifier, and overall charging system.

The first part is just a quick test to see how your charging system is operating. Here were my first results:

The test started out well, but ended up showing that the battery is not being charged very well when the system is under load. With these results it was time to dig into the GS Resources Stator Pages to see where improvements could be made.Part 4 includes the fault find flow chart.

Most problems in low charging rates are do to the 35 year old wiring, corroded electrical connections, and some of the convoluted paths that the electrical currents must travel. The existing wiring has a short negative lead from the regulator/rectifier to the battery box and then another lead from there to the negative terminal of the battery for the ground. This was the first culprit, so I ran a new ground wire directly from the regulator/rectifier to the battery negative terminal and cleaned the connections on the positive side which had better existing wiring gauge.

The picture on the left shows the original rectifier ground which had a light gauge wire, a bullet connector, and two ring terminals bolted to the battery box before the final ring terminal was connected to the negative battery terminal. The right picture shows a new 12 gauge wire for the ground direct between the regulator/rectifier and the negative battery terminal.

Wish I had checked the voltage drop on the negative side before replacing it, but the new negative connection now only experiences a 50mV drop. The positive side is 0.2v still within tolerance of the service manual and stator papers.

Second pass at the quick test:

Key-off = Normal 12.7v-12.9v: 12.8 volts

At idle (1,500 rpm) = Normal 12.6v-13.2v: 14.2 volts

At 2,500 rpm = Normal 13.5v-14.0v: 13.8 volts

At 5,000 rpm = Normal 14.0v-15.0v: 13.9 volts

Key Off = Normal 12.8v-13.0v: 13.2 volts

Still a little strange to see the increase at the idle voltage, but the 2,500 and 5,000 rpm tests were improved to 13.8 volts. Sufficient to ensure that the battery is charging if not the perfect results yet.

The other test then determine the health of the stator. Mine passed most of the tests. The first test checks the resistance between each of the stator leads. Each was 0.6 ohm with desired range of 0.5-2 ohms. The next test was for alternating current across each pair of the stator leads. The stator is producing 89 volts of alternating current at 5,000 rpm across each of the 3 legs of the stator. The manual calls for 80 volts AC at 5,000 rpm. The test of stator lead to ground fault also passed with each leg indicating infinite resistance (no path to ground), but the stator papers have their own test that check for AC volts from lead to ground at 5,000 rpm. Although the stator passed the simple test for ground shorts, this test was showing voltage flowing. I did another test with a test light to try and confirm this result. The light did not come on…

The conclusion is that the stator has life left in it, but that the regulator/rectifier should be replaced to make sure that the stator remains healthy. I have order a new regulator/rectifier that other users have experienced good results with. The unit is a SH775, Polaris part number 4012941.

Once the new R/R arrives, I will also work on improving a single point ground for the wiring system to make the electrical system as robust as possible.